Thousands of academics in Turkish universities stand accused of either having supported terrorism or the attempted coup against President Recep Tayyip Erdoğan in July 2016. Theoretical physicist Ali Kaya is one of them. He was arrested three months after the failed coup and held for more than a year before his trial took place. On 20 December, a court declared him guilty of being a member of a terrorist organization and sentenced him to six years of imprisonment — but released him early owing to the time he had already served in prison while awaiting trial. Kaya says that he is innocent and is appealing against the verdict. In the meantime, he has been suspended from his academic post, and he has yet to learn whether his university, Boğaziçi University in Istanbul, plans to fire him or to await the outcome of the appeal.

Kaya says that while in prison, he kept his sanity by continuing his work on fundamental topics in cosmology. He wrote three research papers during his incarceration, on topics including inflation theory and cosmological perturbation theory. After his release, he posted the papers on the preprint server arXiv. Each contains a footnote that he dedicates to his friends in jail “who made my stay bearable at hell for 440 days between 7.10.2016 and 20.12.2017. I am also indebted to the colleagues who show support in these difficult times.”

Ali Kaya

Nature interviewed Kaya by Skype about his experiences.

What access did you have to research materials while in the prison?

Of course there was no Internet. Nothing digital — not even a pocket calculator — was allowed. No books could be brought in. Nothing in a foreign language was allowed in the jail. One of my students Google-translated some research papers for me into Turkish, but they were held back on suspicion that they included secret codes — presumably because they contained so many equations.

I worked up the research ideas I had already in my head before my arrest. Of course, it took much longer than it would have done if I had been at my computer. I had to start from basic formulae and derive things myself.

But time is something you have plenty of in prison. OK, I could not do ground-breaking work, but I think the papers I produced are solid, and I expect to get them published in good journals.

What were the general conditions like for you there?

Probably the conditions were better than in some other prisons in Turkey. Prisoners came and went. At times there were as many as 30 people, but on average, there were around 20 of us in 140 square metres. The space was divided into several small rooms for sleeping and a larger area that had a television. We were allowed into an adjacent small yard during the day.

Presumably, these conditions were not as cosy for doing research as they might sound?

No. Sure, it sounds cool to say you did research in prison — but prison is a bad place and I wouldn’t recommend it! The worst thing was the lack of contact. We were only allowed family visits for one hour a week, usually speaking through a glass partition on the telephone. We were also allowed a ten-minute phone call every two weeks. And I could speak to my lawyer once a week.

The first night in jail was the worst time of my life. I never gave up hope, but in prison you do often get a feeling that you might never get out, and nights are the worst.

But I told myself “They can take my freedom, but they can’t keep me from doing physics.”

How did you find quiet time to work in such a crowded space?

I was fortunate in my cellmates, many of whom were facing similar charges to me. Many were teachers. There was another assistant professor, and a doctor. We all got on well and the atmosphere was peaceful and respectful. I could sit at a little table with pen and paper and do my work.

You were in prison for almost 438 days: how did you spend all of that time?

I tried to learn Arabic, I played volleyball with others in the yard and I watched soccer on television. And I worked for several hours most days: that’s what kept me sane.

How did your university respond to your arrest?

I was lucky that my university only suspended me. Many other universities sacked those arrested on suspicion of supporting the coup.

What were the grounds for your arrest?

Because of my appeal, I prefer not to speak too much about it. Basically I was accused of being a terrorist — officially, being a member of a terror organization. But I can say that the evidence was abstract and absurd. For example, one of the arguments in my official indictment was that I had visited the United States and Canada, countries favoured by supporters of the movement that the government believes was behind the coup. The reasons for my travel had been academic: I had been on sabbatical at McGill University in Montreal, Canada, and I held a seminar at the Massachusetts Institute of Technology in Cambridge and Tufts University in nearby Boston.